Drive device for electric bicycle and assembly for drive device for electric bicycle

Abstract

The invention relates to a driving device for an electric bicycle and an assembly for a driving device for an electric bicycle. In at least one embodiment, the drive device (100) comprises a planetary gearbox (2) having a planet carrier (20) which is mounted rotatably about an axis of rotation (A) by means of a radial bearing (4) and an axial bearing (5).

Description

Technical Field

[0001] A drive unit for an electric bicycle is described. Additionally, components for the drive unit of an electric bicycle, a method for assembling the drive unit of an electric bicycle, and the electric bicycle itself are described. Background Technology

[0002] Bicycles are a cost-effective, easy-to-use, and emission-free mode of transportation. They have also become popular as sports and fitness equipment, with certain types proving particularly well-suited for a variety of sporting applications.

[0003] In recent years, there has been a growing enthusiasm for electric bicycles (especially so-called "electric-assist bicycles"), despite their higher weight and price compared to conventional bicycles. In the case of electric bicycles, providing a reliable drive mechanism is crucial.

[0004] One task is to determine a drive mechanism for an electric bicycle that facilitates efficient and low-wear operation. Other tasks include determining the components for such a drive mechanism, methods for assembling it, and the electric bicycle incorporating it. Summary of the Invention

[0005] First, the drive mechanism used in electric bicycles will be described in detail.

[0006] In at least one embodiment, the drive unit includes a planetary gearbox with a planetary carrier, wherein the planetary carrier is mounted in a manner rotatable about a rotational axis by means of radial and axial bearings.

[0007] This invention is particularly based on the understanding that, in addition to radial forces, axial forces can also act on the planetary carrier in the drive unit. By combining radial and axial bearings for mounting the planetary carrier, all forces can be effectively absorbed, thereby minimizing wear on the drive unit. This also results in good power transmission and low noise levels.

[0008] In the drive unit, the planet carrier is mounted such that it can rotate about its axis of rotation. This specifically means that the planet carrier can rotate relative to the housing of the drive unit. Unless otherwise stated, the direction parallel to the axis of rotation of the planet carrier is referred to herein and hereinafter as the "axial direction" or simply "axial". Furthermore, unless otherwise indicated, the directional terms "radial" and "azimuth" refer to this axis of rotation. The planet carrier is, for example, rotationally symmetrical about its axis of rotation.

[0009] The planetary carrier is rotatably mounted by means of radial and axial bearings. The radial and axial bearings are, in particular, roller bearings. For example, only one radial bearing and one axial bearing are used for the rotatable mounting of the planetary carrier. The radial bearing absorbs forces perpendicular to the axis of rotation of the planetary carrier, i.e., radial forces, while the axial bearing absorbs forces parallel to the axis of rotation, i.e., axial forces. The radial bearing is, for example, supported by the planetary carrier. The radial and axial bearings are specifically arranged in opposite axial regions of the planetary carrier; that is, the planetary carrier is partially positioned axially between the radial and axial bearings.

[0010] In addition to the planet carrier, the planetary gearbox includes planetary gears rotatably mounted on the planet carrier, as well as a ring gear and a sun gear. The planetary gears mesh with the sun gear and the ring gear. The ring gear may be fixed to the housing in a rotationally fixed manner, meaning that the ring gear does not rotate during operation. The sun gear rotates, for example, about the same axis of rotation as the planet carrier. The axes of rotation of the planetary gears extend parallel to or substantially parallel to the axis of rotation of the planet carrier. During operation, the axes of rotation of the planetary gears rotate about the axis of rotation of the planet carrier. The planet carrier may be made of metal. The planetary gears may be partially made of plastic.

[0011] For example, the planetary gears are mounted in a manner that allows them to rotate relative to the planet carrier via needle roller bearings. The use of needle roller bearings helps to counteract the tilting of the planetary gears relative to the planet carrier.

[0012] To allow the planetary gears to be rotatably mounted on the planet carrier, the planetary gears may have bolts or pins that insert through or into recesses in the planet carrier. Alternatively, the planet carrier may have bolts or bushings that insert through holes in the planetary gears.

[0013] A planetary gearbox may have two or more planetary gears, for example, three planetary gears. All planetary gears are then rotatably mounted on a planet carrier. Specifically, each planetary gear is rotatably mounted on the planet carrier via needle roller bearings. All features disclosed for one planetary gear are also disclosed for all other planetary gears in the planetary gearbox.

[0014] According to at least one embodiment, the axial bearing has an elongated rolling element. The longitudinal axis of the rolling element extends, for example, in the radial direction. The rolling element of the axial bearing can be cylindrical or tapered. The axial bearing can be a needle roller bearing. The radial bearing is, for example, a ball bearing.

[0015] According to at least one embodiment, the axial bearing is arranged radially on the outer periphery of the planet carrier. This means that the axial bearing is arranged on the planet carrier as far away as possible from the axis of rotation of the planet carrier. Therefore, the axial bearing has a particularly large support width and can absorb axial forces particularly well.

[0016] According to at least one embodiment, the axial bearing and the planetary gears of the planetary gearbox are at least partially at the same height in the radial direction. In other words, there exists a region of the axial bearing that is spaced radially from the axis of rotation of the planet carrier by a distance as far as the region of at least one planetary gear. Specifically, the radial bearing is further radially away from the axis of rotation of the planet carrier than from the axis of rotation of the planetary gears. Alternatively or additionally, the axial bearing and the ring gear of the planetary gearbox are at least partially at the same height in the radial direction.

[0017] According to at least one embodiment, the axial clearance of the planetary carrier in the drive unit is at most 0.3 mm, at most 0.2 mm, or at most 0.1 mm. This means that during operation, the planetary carrier can be displaced in a direction parallel to the axis of rotation by at most 0.3 mm, at most 0.2 mm, or at most 0.1 mm. This small axial clearance of the planetary carrier also keeps the maximum angle at which the planetary carrier can tilt during operation very small. This small axial clearance can be achieved, in particular, by a small tolerance chain in the axial direction. The axial movement of the planetary carrier is limited, for example, by stops provided on two sides of the planetary carrier in the axial direction.

[0018] According to at least one embodiment, the thrust washer of the axial bearing is directly opposite the support element of the drive unit in the axial direction. The support element, for example, forms one of the two stops described above. For example, the support element is part of the housing or fixed relative to the housing, i.e., arranged in a non-movable manner relative to the housing. The support element may, in particular, be a radially extending section of the housing. The thrust washer is the washer of the axial bearing on which the rolling elements of the axial bearing roll.

[0019] The fact that the two elements are opposite each other in the axial direction means that, when viewed parallel to the axis of rotation of the planet carrier, one element at least partially covers the other. In other words, the two elements are at least partially at the same height in both the radial and azimuth directions. The fact that the elements are directly opposite each other means that, apart from gaps filled at most with air or lubricant, no other elements, especially no other solid bodies containing the drive mechanism, are arranged between the elements.

[0020] According to at least one embodiment, another thrust washer of the axial bearing is directly opposite the planet carrier in the axial direction. In particular, the planet carrier is spaced apart from the support element in the axial direction by the axial bearing.

[0021] According to at least one embodiment, the ring of the radial bearing is axially opposed to another support element of the drive mechanism. This other support element forms the other of the two stops mentioned above. Specifically, the other support element is part of the housing or fixed relative to the housing, i.e., arranged in a non-movable manner relative to the housing. The other support element is, for example, a radially extending housing segment. The ring is specifically the outer ring of the radial bearing. The rolling elements of the radial bearing operate on the ring.

[0022] According to at least one embodiment, another ring of the radial bearing is directly opposite the planet carrier in the axial direction. This other ring is specifically the inner ring of the radial bearing. This other ring can be spaced apart from the planet carrier by an O-ring. The rolling elements of the radial bearing operate on this other ring.

[0023] According to at least one embodiment, some or all of the aforementioned elements that are directly opposite each other are adjacent to each other. At least, the sum of the axial distances between the aforementioned directly opposite elements is at most 0.1 mm, at most 0.05 mm, or at most 0.02 mm. Since only the axial bearing and the radial bearing are arranged axially between the planet carrier and the two support elements, the tolerance chain in the axial direction remains small, thereby achieving a small axial clearance of the planet carrier.

[0024] According to at least one embodiment, the radial bearing is directly coupled to both the planetary carrier and the drive unit housing. Specifically, the radial bearing abuts the housing and the planetary carrier in the radial direction. For example, the outer ring of the radial bearing abuts the housing in the radial direction, and the inner ring of the radial bearing abuts the planetary carrier in the radial direction. In the region where the radial bearing abuts the housing in the radial direction, the housing, for example, is formed with a single wall, and its surface opposite the radial bearing forms the outer surface of the drive unit.

[0025] Since radial bearings are adjacent to both the housing and the planetary carrier in the radial direction, the tolerance chain in the radial direction is also kept small, which also keeps the maximum tilt angle of the planetary carrier small.

[0026] According to at least one embodiment, the planetary gear is arranged axially between the axial bearing and the radial bearing.

[0027] According to at least one embodiment, the radial bearing is located at at least partially the same height as the planetary gear in the radial direction. For example, the radial bearing protrudes radially beyond the axis of rotation of the planet carrier beyond the planetary gear. In particular, the radial bearing is spaced further away from the axis of rotation of the planet carrier in the radial direction than the axis of rotation of the planetary gear. Alternatively or additionally, the radial bearing may be located at at least partially the same height as the ring gear of the planetary gearbox in the radial direction.

[0028] According to at least one embodiment, the inner diameter of the radial bearing is larger than the inner diameter of the axial bearing. For example, the inner diameter of the radial bearing is at least 4 cm or at least 5 cm.

[0029] By positioning the radial bearings away from the axis of rotation, the planetary carrier can be precisely aligned and stably maintained in its radial position during operation. Large radial bearings also help counteract tilting.

[0030] According to at least one embodiment, the drive device further includes an electric motor and an output terminal. The electric motor is connected to the output terminal via a planetary gearbox to transmit torque from the electric motor to the output terminal.

[0031] In other words, the planetary gearbox connects the electric motor to the output. Specifically, the planetary gearbox is configured to increase the torque transmitted by the electric motor. For example, the planetary gearbox is axially positioned between the electric motor and the output.

[0032] An electric motor consists of a stator and a rotor. For example, an electric motor is an internal rotor motor.

[0033] The output end is a component of the drive unit, through which torque is transmitted from the drive unit. For example, the output end includes an output shaft. The output shaft can be a hollow shaft. For example, the pedal shaft of the drive unit extends through the output shaft. The output shaft can be connected to the chain links or chain link star frame in a rotationally fixed manner. Alternatively or additionally, the output shaft has a joint for engagement with the chain links or chain link star frame.

[0034] According to at least one embodiment, the drive unit further includes a bevel gear stage. Specifically, the bevel gear stage connects the planetary gearbox to the output end. In other words, the bevel gear stage connects the planetary gearbox and the output end. The bevel gear stage is configured, for example, to further increase the torque transmitted by the planetary gearbox. The bevel gear stage may be a 90° bevel gear stage. The planetary gearbox is, for example, axially arranged between the electric motor and the bevel gear stage.

[0035] Due to the connection between the planetary gearbox and the bevel gear stage, high tilting moments and large axial forces can act on the planetary carrier during drive operation. These forces are well supported by axial and radial bearings.

[0036] According to at least one embodiment, the bevel gear stage is connected to the planetary carrier without an intermediate gear stage. In other words, the torque transmitted by the planetary gearbox is the torque supplied to the bevel gear stage. For example, components of the planetary gearbox are connected to the bevel gears of the bevel gear stage in a rotationally fixed manner.

[0037] According to at least one embodiment, the radial bearing is arranged axially between the axial bearing and the second bevel gear of the bevel gear stage. In particular, the radial bearing is arranged at least partially at the height of the planet carrier in the axial direction.

[0038] According to at least one embodiment, the support width of the axial bearing is greater than the axial distance between the engagement point of the radial bearing and the bevel gear of the bevel gear stage. This is specifically used to keep the axial force absorbed by the axial bearing as low as possible. On the other hand, the tilting point of the planetary carrier is located near the radial bearing in the axial direction. Since the axial distance between the engagement point of the radial bearing and the bevel gear is small relative to the support width, the force that causes the tilting can be kept relatively small. The engagement point of the bevel gear is understood here as the area where the teeth of the two bevel gears mesh with each other.

[0039] According to at least one embodiment, the planet carrier is coupled to the first bevel gear of the bevel gear stage in a rotationally fixed manner. This means that during operation, the first bevel gear and the planet carrier rotate together about the planet carrier's axis of rotation at the same speed and in the same direction. In particular, the first bevel gear is directly connected to the planet carrier, for example, via a form-fit and / or force-fit connection. Alternatively, the planet carrier and the first bevel gear may also be integrally formed with each other. The first bevel gear is, for example, a bevel pinion.

[0040] Because of the connection between the first bevel gear and the planetary carrier, and the stable installation of the planetary carrier by means of axial and radial bearings, the first bevel gear is also installed in a particularly stable position, which is advantageous for high power transmission.

[0041] According to at least one embodiment, the bevel gear stage includes the aforementioned second bevel gear. The second bevel gear meshes with the first bevel gear. For example, the second bevel gear is connected to the output end without an intermediate gear stage. The axis of rotation of the second bevel gear extends obliquely or perpendicularly to the axis of rotation of the planet carrier or the first bevel gear. The axis of rotation of the output end is, for example, parallel or the same as the axis of rotation of the second bevel gear. In particular, the axis of rotation of the planet carrier lies in a plane perpendicular to the axis of rotation of the output end. The second bevel gear is, for example, a ring gear. The drive device is, for example, an orthogonal drive.

[0042] According to at least one embodiment, the second bevel gear is connected to the output end via a flywheel. For example, the flywheel connects the second bevel gear to the output shaft at the output end.

[0043] According to at least one embodiment, the output shaft at the output end is connected to the pedal shaft of the drive unit via a flywheel. The flywheel is, for example, a toothed disc flywheel. In particular, the pedal shaft passes through the output shaft, which is formed as a hollow shaft.

[0044] According to at least one embodiment, the pedal shaft extends obliquely or perpendicularly relative to the rotation axis of the planetary carrier. In other words, the rotation axis of the pedal shaft is obliquely or perpendicularly relative to the rotation axis of the planetary carrier. For example, the angle between the pedal shaft and the rotation axis of the planetary carrier, or the angle between the rotation axis of the pedal shaft and the rotation axis of the planetary carrier, is between 80° and 100°, including 80° and 100°.

[0045] Next, the electric bicycle will be described. The electric bicycle includes a drive unit according to one exemplary embodiment of the exemplary embodiments described herein.

[0046] Next, components for a drive unit for an electric bicycle and a method for assembling the drive unit will be described in detail. Specifically, the components are configured for assembling a drive unit according to one embodiment described herein. In this regard, all features disclosed in connection with the drive unit are also disclosed for the components and methods, and all features disclosed in connection with the components and methods are also disclosed for the drive unit.

[0047] In at least one embodiment, the drive unit for an electric bicycle includes a planetary carrier for a planetary gearbox and radial and axial bearings for mounting the planetary carrier in a manner capable of rotating about a rotational axis.

[0048] In addition to the planetary carrier, radial bearings, and axial bearings, the assembly may include a housing portion, such as a bottom support housing. The planetary carrier is rotatably mounted relative to this housing portion. The housing portion of the assembly may be connected to one or more additional housing portions of one or more additional assemblies to form a housing for a drive mechanism. Furthermore, the assembly may have at least one planetary gear and one ring gear. Additionally, the assembly may have a first bevel gear connected to the planetary carrier in a rotationally fixed manner for use in a bevel gear stage. Additionally, the assembly may include a pedal shaft.

[0049] Another component includes, for example, an electric motor having a stator, rotor, and motor shaft. Another component may include a support element for a thrust washer used in an axial bearing. Furthermore, another component includes a housing portion, such as a motor housing.

[0050] Another component includes, for example, an output end and a second bevel gear for the bevel gear stage coupled to the output end. Additionally, another component includes a housing portion, such as a cover.

[0051] In at least one embodiment, the component and another component are connected to each other, particularly by connecting their housing portions to each other, for the assembly of the drive unit. During this process, for example, a support element of the other component, formed by another housing portion of the other component, is arranged axially opposite to the thrust washer of the axial bearing. During assembly, the motor shaft can be inserted through the planetary carrier.

[0052] According to at least one embodiment, the component is connected to another component in the method. The housing portion of the first component and the housing portion of the second component can be screwed together. Additionally, the bevel gear of the first component and the bevel gear of the second component can engage. Furthermore, for example, the pedal shaft of the first component is pushed through the output shaft of the second component.

[0053] In the following sections, the drive unit, components, methods for assembling the drive unit, and electric bicycle described herein are explained in more detail with reference to the accompanying drawings, based on exemplary embodiments. The same reference numerals indicate the same elements in the various figures. Since elements or components in the various figures are functionally identical, their descriptions will not be repeated in each of the following figures. For clarity, corresponding reference numerals may not be provided for elements in all figures. Attached Figure Description

[0054] Figure 1 An exemplary implementation of an electric bicycle is shown.

[0055] Figure 2 An exemplary embodiment of the drive device is shown.

[0056] Figure 3 Another exemplary embodiment of the drive device is shown.

[0057] Figure 4 An exemplary implementation of the component is shown.

[0058] Figure 5 An exemplary implementation of another component is shown.

[0059] Figure 6 The location is shown in an exemplary embodiment of the assembly method.

[0060] Figure 7 An exemplary implementation of yet another component is shown.

[0061] Figure 8 Another location is shown in an exemplary implementation of the assembly method. Detailed Implementation

[0062] Figure 1An electric bicycle 200 with a bicycle frame 110 is schematically shown, the bicycle frame 110 having a lower frame section 120. The lower frame section forms a downtube. The lower frame section 120 extends toward the bottom bracket of the electric bicycle, wherein the bottom bracket includes a pedal axle 90. The pedal axle 90 is part of a drive unit 100 mounted in the bicycle.

[0063] Figure 2 A first exemplary embodiment of the drive unit 100 is shown in cross-section. The drive unit 100 has a planetary gearbox 2. The planetary gearbox 2 includes a planet carrier 20, which is mounted in a housing 7 in a manner rotatable about a rotation axis A. One or more planetary gears 21 are mounted on the planet carrier 20 in a manner rotatable relative to the planet carrier 20. Figure 2 Only the portion of the drive unit 100 above the rotation axis A is shown.

[0064] The planetary gearbox 2 also includes a sun gear 26. At least one planet gear 21 meshes with the sun gear 26, which is also mounted, for example, in a manner rotatable about the axis of rotation A. Additionally, at least one planet gear 21 meshes with a ring gear 27 of the planetary gearbox 2. The ring gear 27 can be mounted in a manner rotatable about the axis of rotation A, or it can be connected to the housing 7 in a rotationally fixed manner; that is, the ring gear 27 can be mounted as non-rotatable.

[0065] Planetary gearbox 2 connects electric motor 1 to output terminal 8. Electric motor 1 includes rotor 11 and stator 12. Motor shaft 10 of electric motor 1 is fixed in rotation to sun gear 26 of planetary gearbox 2. Alternatively, motor shaft 10 may also be fixed in rotation to ring gear 27 or planet carrier 20. Output terminal 8 is fixed in rotation to planet carrier 20. In particular, output shaft 80, which is formed as a hollow shaft 80, is fixed in rotation to planet carrier 20 and chain link 82 or chain link star carrier 82.

[0066] The planetary gearbox 2 in the drive unit 100 is used to transmit torque from the electric motor 1 to the output end 8. With the help of the planetary gearbox 2, the speed decreases and, in particular, the torque increases. The transmitted torque can be used to assist the pedaling motion of the electric bicycle rider. In this case, the pedal shaft 90 on which the rider manually applies torque is connected to the output shaft 80 via the flywheel 92, so that both the torque applied by the rider and the torque applied by the electric motor 1 can be transmitted to the output end 8.

[0067] The planetary carrier 20 is rotated within the housing 7 by means of a radial bearing 4 and an axial bearing 5. The radial bearing 4 includes an inner ring 42, a rolling element 40 (e.g., in the form of balls), and an outer ring 41. The outer ring 41 abuts the housing 7 in the radial direction. In the axial direction, the outer ring 41 abuts the support element 71 or is arranged at least axially opposite to the support element 71. The inner ring 42 abuts the planetary carrier 20 in the radial direction. In the axial direction, the inner ring 42 abuts the planetary carrier 20 or is arranged at least axially opposite to the planetary carrier 20.

[0068] The thrust washer 51 of the axial bearing 5 is arranged adjacent to or at least directly opposite the support element 70 in the axial direction, and the rolling element 50 of the axial bearing 5 rolls on the thrust washer 51. The support element 70 is also part of the housing 7. The rolling element 50 of the axial bearing 5 can be a cylindrical or tapered member. The second thrust washer 52 of the axial bearing 5 is arranged adjacent to or at least directly opposite the planetary carrier 20 in the axial direction, and the rolling element 50 rolls on the second thrust washer 52.

[0069] The described arrangement keeps the tolerance chains for the radial and axial clearances of the planet carrier 20 low. For example, the axial clearance of the planet carrier 20 is at most 0.3 mm. This allows, for example, tilting of the planet carrier 20 within the housing to be kept low or avoided.

[0070] Figure 3 Another exemplary embodiment of the drive unit 100 is shown in cross-sectional view. The drive unit 100 includes a housing 7 having three interconnected housing portions 70, 71, and 74. Housing portion 70 forms a motor housing in which an electric motor 1 is housed. Housing portion 71 forms a bottom support housing in which, among other things, a planetary gearbox 2 is housed. The motor housing 70 and the bottom support housing 71 are connected to each other via a sealing sleeve 72. Housing portion 74 forms an output-side cover that is screwed onto the bottom support housing 71.

[0071] The electric motor 1 includes a stator 12 and a rotor 11. The electric motor 1 is an internal rotor type motor. During operation, the rotor 11 rotates relative to the stator 12 or the housing 7 about a rotation axis A. The rotor 11 is coupled to a motor shaft 10 and also causes the motor shaft 10 to rotate about a rotation axis A during operation. The rotation axis A extends through the motor shaft 10. The motor shaft 10 is made, for example, of stainless steel or surface-hardened steel. The electric motor 1 is mounted in the housing 7 by means of a motor bearing 16.

[0072] The motor shaft 10 protrudes axially from the rotor 11 and into the planet carrier 20 of the planetary gearbox 2. In the opposite axial direction, a magnet 14 is arranged at the end of the motor shaft 10, spaced apart from the motor shaft 10 by a connector 15. The connector 15 is made of, for example, aluminum and is intended to reduce the influence of the steel motor shaft 10 on the magnetic field generated by the magnet 14. The drive unit 100 also includes a sensor (not shown) that detects the magnetic field of the magnet 14 and thereby qualitatively and quantitatively detects the position of the motor shaft 10.

[0073] The planetary gearbox 2 forming the first gear stage of the drive unit 100 includes a planet carrier 20, three planetary gears 21, a sun gear 26, and a ring gear 27. Figure 3 The first planetary gear 21, i.e., the planetary gear above the axis of rotation A, is shown in cross-sectional view, while the other planetary gear 21 is shown in top view. The planetary gears 21 are mounted on the planet carrier 20 such that they are rotatable. Similarly, the planet carrier 20 is mounted such that it is rotatable about the axis of rotation A by means of two roller bearings 4, 5. In the present case, the planet carrier 20 has bushings 25 inserted through holes in the planetary gears 21.

[0074] The sun gear 26 for the planetary gearbox 2 is integrated into the motor shaft 10, meaning the motor shaft 10 and the sun gear 26 are integrally formed or shaped into a single piece. Specifically, the teeth of the sun gear 26 are formed in the motor shaft 10 by means of a forming process, such as rolling. This means that the teeth of the sun gear 26 are manufactured without milling, which can be identified by the absence of milling marks. The teeth of the sun gear 26 are helical, meaning they do not extend parallel to the axis of rotation A, but are oblique to or helical around the axis of rotation A.

[0075] The teeth of the sun gear 26 mesh with the corresponding helical teeth of the planet gear 21. Rotation of the motor shaft 10 causes the planet gear 21 to rotate, which in turn causes the planet carrier 20 to rotate about the axis of rotation A. The planet gear 21 rolls on a fixed ring gear 27. The ring gear 27 is fixed to the housing 7, for example, and therefore does not rotate relative to the housing 7 during operation.

[0076] The molding process used in the manufacturing of the teeth of the sun gear 26 results in a particularly smooth tooth surface. The teeth of the planetary gear 21 are made of plastic, for example. When plastic is used for the planetary gear 21, the smooth surface of the sun gear 26 is particularly advantageous because it minimizes wear. Planetary gears made entirely or partially of plastic are more tolerant of manufacturing tolerances and less sensitive to tilting relative to the planet carrier 20.

[0077] In fact, the tilting torque acts on planetary gear 21, which tends to tilt planetary gear 21 relative to planet carrier 20. This tilting torque is largely generated by the use of helical teeth. However, helical teeth are advantageous in terms of high power transmission and low noise generation.

[0078] To minimize and effectively counteract the tilt of the planetary gears 21 relative to the planet carrier 20, each planetary gear 21 is rotatably mounted on the planet carrier 20 by means of a needle roller bearing 22. The needle-shaped or cylindrical rolling elements 24 of the needle roller bearing 22 roll on a bushing 25 on one side and on a sleeve 23 on the other side. The bushing 25 and sleeve 23 are made of, for example, metal. The sleeve 23 is part of the planetary gear 21 and is encapsulated or overmolded with plastic, thereby forming the teeth of the planetary gear 21 with this plastic. By reducing the relative tilt between the planetary gears 21 and the planet carrier 20 due to the use of the needle roller bearings 22, wear on the drive unit 100 can be reduced and its performance improved.

[0079] The planetary carrier 20 has a recess at its axial end opposite to the motor 1. The rotation axis A extends through this recess. The planetary carrier 20 has internal threads in the region of the recess. The first bevel gear 30, i.e., the pinion, of the bevel gear stage 3 is screwed into these internal threads. The bevel gear stage 3 forms the second gear stage of the drive unit 100. The first bevel gear 30 has a cylindrical section with external threads and a conical section with external teeth. The cylindrical section is screwed into the recess of the planetary carrier 23, thereby securing the first bevel gear 30 to the planetary carrier 23 and making it immovable relative to the planetary carrier 20; that is, the first bevel gear 30 is fixed to the planetary carrier in a rotationally fixed manner. The first bevel gear 30 is precisely aligned relative to the planetary carrier 20 by means of a centering collar. The conical section protrudes axially from the planetary carrier 20 away from the electric motor 1.

[0080] The first bevel gear 30 has a recess that opens in the direction of the electric motor 1, and the motor shaft 10 is guided into the recess. The motor shaft 10 can rotate freely within the recess. Figure 3 Unlike what is depicted, the motor shaft 10 can be rotatably mounted in the recess by means of a bearing.

[0081] The section of the motor shaft 10 that protrudes into the recess of the bevel gear 30 has no teeth. This section, for example, forms an engagement for a so-called "independent" test of the electric motor 1, i.e., a test in the uninstalled state.

[0082] During operation, the planetary carrier 20 and the first bevel gear 30 rotate together about the rotation axis A. The bevel gear stage 3 has a second bevel gear 31 in the form of a ring gear. The second bevel gear 31 is mounted such that it can rotate about the pedal axis P, which extends perpendicular to the rotation axis A. Therefore, the bevel gear stage 3 is a 90° bevel gear stage.

[0083] The second bevel gear 31 is connected via a flywheel 81 to an output shaft 80, which is in the form of a hollow shaft. The output shaft 80 is part of the output end 8. The output end 8 also includes, for example, chain links and / or chain link star brackets (not shown) that are fixed in rotational direction to the output shaft 80. Alternatively, the output shaft 80 may also have only a joint for fixed rotational connection with the chain links or chain link star brackets.

[0084] The pedal shaft 90 extends through the hollow shaft-shaped output shaft 80. The pedal shaft 90 is connected to the output shaft 80. The pedal shaft 90 and the output shaft 80 are rotatably mounted by means of radial bearings 60, 61, also known as main bearings 60, 61. When the rider of the electric bicycle pedals, the pedal shaft 90 rotates about the pedal axis P and drives the output shaft 80 via a flywheel. The electric motor 1 applies torque to the output shaft 80 via a planetary gearbox 2 and a bevel gear stage 3 to assist the rider. The drive unit 100 shown is an orthogonal drive.

[0085] By using a bevel gear stage 3 directly coupled to the planet carrier 20, i.e., coupled to the planet carrier 20 without any additional intermediate gear stages, the drive unit 100 can be designed to be particularly compact while simultaneously providing efficient speed reduction from the electric motor 1 to the output end 8. However, the direct coupling between the planet carrier 20 and the bevel gear stage 3 also results in the bevel gear stage 3 applying axial, radial, and azimuthal forces to the planet carrier 20 during operation of the drive unit 100. These forces attempt to push the planet carrier 20 towards the electric motor 1 and simultaneously tilt the planet carrier 20.

[0086] To effectively absorb the acting radial force, the planetary carrier 20 is mounted in the housing 7 via a large radial bearing 4. The radial bearing 4 has an inner diameter of, for example, 5 cm. The radial bearing 4 is supported by the planetary carrier 20.

[0087] The resulting axial force is absorbed by the axial bearing 5. Specifically, the tilting moment acting on the planetary carrier 20 results in a large axial load on the axial bearing 5. The axial bearing 5 also has a large diameter. Here, the axial bearing 5 is arranged at the outer edge or periphery of the planetary carrier 20, i.e., as far apart as possible radially from the axis of rotation A. Furthermore, elongated rolling elements, such as cylindrical or tapered elements, are used as the rolling elements 50 of the axial bearing 5, thereby distributing the load over a larger area.

[0088] To minimize tilting of the planetary carrier 20, the axial clearance between the radial bearing 4 and the axial bearing 5 is kept particularly small, for example, a maximum of 0.1 mm. This is achieved, in particular, by a small tolerance chain in the axial direction. The small tolerance chain is achieved as follows: the thrust washer 51 of the axial bearing 5 is arranged axially opposite to the radial extension of the support element, i.e., the motor housing 70, and the rolling element 52 rolls on the thrust washer 51. Another thrust washer 52 of the axial bearing 5 is arranged axially opposite to the planetary carrier 20. Furthermore, the inner ring 42 of the radial bearing 4 is arranged axially opposite to the planetary carrier 20, and the rolling element 40 of the radial bearing 4 rolls on the inner ring. The outer ring 41 of the radial bearing 4 is arranged axially opposite to another support element, i.e., a portion of the bottom support housing 71. The motor housing 70 and the bottom support housing 71 are connected to each other in an axially immovable manner. The elements that are axially opposite to each other are abutted against each other or spaced apart from each other by at most a narrow gap in the axial direction. In particular, the sum of the axial distances between the aforementioned opposing elements is less than 0.1 mm.

[0089] When the drive unit 100 is installed and the motor is running, the planetary carrier 20 is pressed axially toward the electric motor 1. The planetary carrier 20 then axially abuts directly against the thrust washer 52, and the thrust washer 51 axially abuts directly against the motor housing 70. This small axial distance ensures that the planetary carrier 20 remains almost completely tilt-free, despite a strong tilting moment.

[0090] Another measure to reduce the tilt of the planet carrier 20 is the small radial clearance between the planet carrier 20 and the first bevel gear 30. For this purpose, the first bevel gear 30 is securely connected to the planet carrier 20. The radial clearance of the planet carrier 20 is kept low by the fact that the radial bearing 4 for radial mounting of the planet carrier 20, arranged radially between the planet carrier 20 and the housing 7, abuts against the planet carrier 20 with its inner ring 42 and against the housing 7 with its outer ring 41 in the radial direction. No intermediate elements are used between the radial bearing 4 and the housing 7, as these elements could increase the radial clearance of the planet carrier 20 or the first bevel gear 30. In other words, the radial clearance between the first bevel gear 30 and the planet carrier 20 is kept low by using fewer elements in the radial tolerance chain. This means that the planet carrier 20 can only tilt to a limited extent.

[0091] In summary, the use of the aforementioned radial bearing 4 and axial bearing 5 helps to counteract the tilting of the planetary carrier 20 and effectively absorb forces. This makes the drive unit 100 particularly powerful while ensuring low wear.

[0092] Performance is further enhanced by the precise alignment of bevel gears 30 and 31. This is achieved, on the one hand, through the low-clearance mounting of the planetary carrier 20 and the first bevel gear 30, and on the other hand, through the low-clearance mounting of the second bevel gear 31. For this purpose, the second bevel gear 31 is fixedly, i.e., immovably, connected to the output shaft 80. The output shaft 80 is mounted via a radial bearing 60 such that it can rotate about the axis of rotation P, wherein the radial bearing 60 is in direct contact with both the output shaft 80 and the cover 74. The cover 74 is then securely connected to the bottom support housing 71. Similarly, to reduce the clearance of the second bevel gear 31 in the axial direction parallel to the axis of rotation A, the rotatable mounting of the second bevel gear 31 about the axis of rotation P is achieved through a small number of movable elements between the housing 7 and the second bevel gear 31.

[0093] The fixed connection between housing parts 71 and 74 is a threaded connection. For this threaded connection, the bottom support housing 71 and the cover 74 have interlocking threads 710 and 740. These threads 710 and 740 extend about the axis of rotation P of the pedal shaft 90. The relative arrangement between housing parts 71 and 74 is secured by a fixing element 742. In this case, the fixing element 742 is a screw screwed into the receiving portion 741 of the housing part 74. Specifically, housing part 74 has two annular segments 743 and 744, which, in the shown cross-sectional view, are formed by the U-shaped region of the third housing part 74; that is, the two annular segments 743 and 744 are spaced apart from each other by a gap in a direction parallel to the axis of rotation P. Each of the two segments 743 and 744 forms a portion of the external thread 740 of the housing part 74. The longitudinal end of the screw 742 presses the second section 744 away from the first section 743, thereby causing the threaded connection between the housing parts 71 and 74 to lock and thus securing the housing parts 71 and 74 in their relative arrangement.

[0094] The second bevel gear 31 has its movement relative to the third housing element 74 in a direction parallel to the axis of rotation P limited by a stop surface. Therefore, the threaded connection between housing portions 71 and 74 allows the second bevel gear 31 to be positioned with particularly high precision along the axis of rotation P. The secure threaded connection then ensures a particularly stable position of the second bevel gear 31 in the direction of the axis of rotation P. In general, the bevel gears 30 and 31 are then aligned with each other with a specific precision, which benefits the performance of the entire drive unit 100.

[0095] Figure 4 It shows the use of Figure 3An exemplary embodiment of the drive unit assembly 101 is described. Assembly 101 includes a bottom support housing 71, a planetary carrier 20, and a first bevel gear 30, which are connected to each other in a rotationally fixed manner and rotatably mounted by means of a radial bearing 4 carried by the planetary carrier 20. Assembly 101 also includes a planetary gear 21, which is rotatably mounted on the planetary carrier 20 by means of a needle roller bearing 22. An axial bearing 5 is arranged on the side of the planetary carrier 20 opposite to the first bevel gear 30. Additionally, a pedal shaft 90 is inserted through the bottom support housing 71. The bottom support housing 71 is made of metal, for example. The bottom support housing 71 is formed as a single piece and encloses the pedal shaft 90 in the direction about the pedal axis P and the planetary carrier 20 in the direction about the rotation axis A.

[0096] Figure 5 It shows the use of Figure 3 An exemplary embodiment of another component 102 of the drive device 100. Component 102 includes a motor housing 70, in which an electric motor 1 having an associated motor shaft 10 is housed.

[0097] In order to assemble Figure 3 The drive unit 200 first connects component 102 to component 101. The resulting device is... Figure 6 As shown in the diagram. During assembly, the motor shaft 10 is pushed through the planetary carrier 20 into the receiving portion of the first bevel gear 30. Additionally, the thrust washer 51 is arranged axially opposite the radially extending section of the motor housing 70. The housing portions 70 and 71 are connected to each other. The dimensions of the various components are selected such that there is no air gap or only a small air gap in the axial direction between the housing portions: bearings 4 and 5 can be axially supported on the housing portions.

[0098] Figure 7 It shows the assembly Figure 3 An exemplary embodiment of another component 104 of the drive unit 100. Component 104 includes a housing portion 74. A fastening element 742 in the form of a screw is inserted into a receiving portion 741 of the housing portion 74, but only to the extent that segments 743 and 744 are not yet clamped relative to each other. Component 104 also includes a bevel gear 31, an output shaft 80, and a radial bearing 60. The bevel gear 31 and the output shaft 80 are rotatably mounted via the radial bearing 60.

[0099] In order to assemble the drive unit, now will Figure 7 The component 104 shown is screwed onto Figure 6 On the device shown in (see Figure 8Push the pedal shaft 90 through the feed passage 745 in the housing portion 74. Screw the housing portions 74 and 71 together until the bevel gears 30 and 31 are positioned in a direction parallel to the axis of rotation P as needed. Then tighten the screw 742 to clamp the segments 743 and 744 relative to each other, thereby clamping the threaded connection between the housing portions 74 and 71. This allows the bevel gears 30 and 31 to be fixed in their relative positions parallel to the axis of rotation P.

[0100] List of reference numerals in the attached figures

[0101] 1. Electric motor

[0102] 2 Planetary Gearbox

[0103] 3 Bevel Gear Stage

[0104] 4 Radial bearings

[0105] 5 Axial bearings

[0106] 7. Casing

[0107] 8 Output terminals

[0108] 10 Motor Shaft

[0109] 11 Rotors

[0110] 12 stators

[0111] 14 Magnets

[0112] 15 Adapters for magnets

[0113] 16 Motor bearings

[0114] 20 planetary carriers

[0115] 21 Planetary Gears

[0116] 22 Needle roller bearings

[0117] 23. Outerwear

[0118] 24 Rolling elements

[0119] 25 Bushing / Bolt

[0120] 26 Sun Gears

[0121] 27. Ring gear

[0122] 30 First bevel gear / conical pinion

[0123] 31 Second bevel gear / ring gear

[0124] 40 Rolling elements

[0125] 41 Outer Ring

[0126] 42 Inner Ring

[0127] 50 Rolling elements

[0128] 51 Thrust Washer

[0129] 52 Thrust Washer

[0130] 60 radial bearing

[0131] 61 Radial bearing

[0132] 70 Motor housing

[0133] 71 Bottom support housing

[0134] 72 Sealing Sleeve

[0135] 74 Covering

[0136] 80 Output Shaft

[0137] 81 Flywheel

[0138] 82 Chain Link / Chain Link Star Frame

[0139] 90 pedal shaft

[0140] 92 Flywheel

[0141] 100 drive unit

[0142] 101 components

[0143] 102 components

[0144] 104 components

[0145] 110 Bicycle Frame

[0146] 120 lower pipe

[0147] 200 electric bicycles

[0148] 710 thread

[0149] 740 thread

[0150] 741 Reception Department

[0151] 742 Fixing Components / Screws

[0152] 743 Part One

[0153] 744 Part Two

[0154] 745 feedthrough section

[0155] A. Rotation axis

[0156] P Pedal axis / rotation axis

Claims

1. A drive unit (100) for an electric bicycle (200), the drive unit (100) comprising: Planetary gearbox (2), wherein the planetary gearbox (2) has a planet carrier (20), wherein, The planetary carrier (20) is mounted in a manner that allows it to rotate about the axis of rotation (A) by means of radial bearings (4) and axial bearings (5).

2. The driving device (100) according to claim 1, wherein, The axial bearing (5) includes an elongated rolling element (50).

3. The driving device (100) according to claim 1 or 2, wherein, The axial bearing (5) is arranged in the radial direction at the outer edge of the planet carrier (20).

4. The driving device (100) according to any one of the preceding claims, wherein, The axial clearance of the planetary carrier (20) in the drive unit (100) is at most 0.3 mm.

5. The driving device (100) according to any one of the preceding claims, wherein, The thrust washer (51) of the axial bearing (5) is directly opposite the support element (70) of the drive device (100) in the axial direction. The other thrust washer (52) of the axial bearing (5) is directly opposite the planet carrier (20) in the axial direction. The ring (41) of the radial bearing (4) is directly opposite to another support element (71) of the drive device in the axial direction. The other ring (42) of the radial bearing (4) is directly opposite the planet carrier (20) in the axial direction.

6. The driving device (100) according to any one of the preceding claims, wherein, The radial bearing (4) is directly connected to both the planetary carrier (20) and the housing (7) of the drive unit (100).

7. The driving device (100) according to any one of the preceding claims further includes: Planetary gears (21) are rotatably mounted on the planet carrier (20), wherein, At least one of the planetary gears (21) is arranged axially between the axial bearing (5) and the radial bearing (4).

8. The driving device (100) according to any one of the preceding claims, wherein, The inner diameter of the radial bearing (4) is larger than the inner diameter of the axial bearing (5).

9. The driving device (100) according to any one of the preceding claims further includes: Electric motor (1). Output terminal (8), where, The electric motor (1) is connected to the output terminal (8) via the planetary gearbox (2) so as to transmit torque from the electric motor (1) to the output terminal (8).

10. The driving device (100) according to claim 9 further includes: A bevel gear stage (3) is located between the planetary gearbox (2) and the output end (8), wherein, The bevel gear stage (3) is connected to the planetary gearbox (2) without an intermediate gear stage.

11. The driving device (100) according to claim 10, wherein, The radial bearing (4) is arranged axially between the axial bearing (5) and the second bevel gear (31) of the bevel gear stage (3).

12. The drive device (100) according to claim 10 or 11, wherein, The support width of the axial bearing (5) is greater than the axial distance between the radial bearing (4) and the bevel gears (30, 31) of the bevel gear stage (3).

13. The drive device (100) according to any one of claims 10 to 12, wherein, The planet carrier (20) is connected to the first bevel gear (30) of the bevel gear stage (3) in a rotationally fixed manner.

14. The drive device (100) according to claim 13, wherein, The second bevel gear (31), which engages with the first bevel gear (30), is connected to the output end (8) without an intermediate gear stage.

15. An assembly (101) for a drive unit (100) of an electric bicycle (200), the assembly (101) comprising: Planetary carrier (20), which is used for planetary gearbox (2). Radial bearing (4) and axial bearing (5) are used to mount the planetary carrier (20) in a manner that allows it to rotate about the axis of rotation (A).

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